Purpose The research aimed to study the effects of size reduction and composting duration of empty fruit bunches (EFB) on straw mushroom production, and to examine the doses of fertilizers commonly used among farmers. Methods The experiment was done in two stages. The first stage was for identifying the optimum physical parameters of EFB, and the second stage focused on enhancing the performance of EFB chosen based on the findings of the first experiment. A randomized complete block design with 3 × 3 factorial arrangement in both stages of the study used the same approach. The first stage had three levels of aggregate sizes factor (S) and three levels of composting duration factor (C) of EFB. The second stage had three levels of NPK factor (N) and three levels of organic fertilizer factor (O). Results Whole stalk EFB had the highest productivity of 2458.47 ± 1015.23 g m −2. The supplementation of fertilizers increased the EFB decomposition rate and productivity to 2950.24 ± 208.50 g m −2 , and nutritive values (particularly for protein content of 41.00 ± 3.79%). Averaged biological conversion efficiency (BCE) was also improved from 3.61 ± 1.22 to 6.56 ± 0.46%. Conclusions EFB did not need to be cut into smaller pieces, and should not be composted for more than 8 days, because there was a tendency to decrease yield. Supplemental fertilizers increased the decomposition rates of EFB as well as the yield and nutritive values of straw mushroom. BCE can potentially be improved by increasing the dosages of fertilizers.

The objective of multi years study was to formulate an alternative organic based fertilizer by mixing a fresh manureand phosphate rock with several different grain sizes conducted in the Field Experimental Station of the Universityof Lampung. Both materials of the fresh manure and phosphate rock were obtained from local sources. Five levelsof mixture of fresh manure and phosphate rock, three levels of grain size of phosphate rock, and two kinds ofcomposting technique were factorial set up. The mixture materials were aerobically composted for 12 weeks. Theresults of the first year study show that (a) the optimum ratio of the mixture of fresh manure and phosphate rock was80% to 20% with the optimum of grain size of phosphate rock < 3 mm; (b) 6-8 weeks of incubation of the mixturematerials has been optimally composted under aerobic conditions of the complete mixture of batch compostedtechnique; (c) the quality of the final produced compost was considered to fulfill the requirement of standard criteriaof organic fertilizer; while (d) the quantity of compost recovered up to 75.07% which was a reliable quantity of massproduction of organic fertilizer.[How to Cite: Nugroho SG, Dermiyati, J Lumbanraja, S Triyono, H Ismono, YT Sari and E Ayuandari. 2012. Optimum Ratio of Fresh Manure and Grain Size of Phosphate Rock Mixture in a Formulated Compost for Organomineral NP Fertilizer. J Trop Soils 17 (2) : 121-128. Doi: 10.5400/jts.2012.17.2.121][Permalink/DOI: www.dx.doi.org/10.5400/jts.2012.17.2.121]

Microbial N2-fixer and P-solubilizer were innoculated in a mixture of fresh manure and phosphate rock formulated as an Organonitrophos fertilizer. The population dynamics of bacteria and fungi growing during the composting process were observed. The inoculation treatments consisted of: K = mixture of 20% phosphate rock and 80% of fresh manure + decomposers (control), N = mixture of 20% phosphate rock and 80% of fresh manure + decomposers + N2-fixer (Azotobacter and Azospirillum sp.) , P = mixture of 20% phosphate rock and 80% of fresh manure + decomposers + P-solubilizer (A. niger and P. fluorescens), and NP = mixture of 20% phosphate rock and 80% of fresh manure + decomposers + N2-fixer + P-solubilizer. The results showed that inoculation of microbial N2-fixer and combination inoculation of N2-fixer and P-solubilizer increased the total bacterial population compared to that of the control as well as the only inoculation of microbial P-solubilizer on the 14th day of observation in which the bacteria reached the highest population. On all the observation days, the population of fungi in the inoculation of microbial P-solubilizer treatment increased significantly compared to that of the control. However, there was no difference between the populations of fungi in the inoculation of N2-fixer and combination inoculation of N2-fixer and Psolubilizer. The genus of fungy identified in the compost of the mixture of fresh manure and phosphate rock were Chytridium sp., Aspergillus sp., Rhizopus sp., and Fusarium sp.[How to Cite : Nugroho SG, Dermiyati, J Lumbanraja, S Triyono, H Ismono. 2013. Inoculation Effect of N2-Fixer and P-Solubilizer into a Mixture of Fresh Manure and Phosphate Rock Formulated as Organonitrofos Fertilizer on Bacterial and Fungal Populations. J Trop Soils, 18 (1): 75-80. doi: 10.5400/jts.2013.18.1.75][Permalink/DOI: www.dx.doi.org/10.5400/jts.2013.18.1.75]

Efforts to increase the production of sweet corn can be done with the application of fertilizers, either inorganic, organic orits combination. In addition, the application of soil amendments such as biochar is also expected to improve soil fertility that will indirectly increase the production of sweet corn.Organonitrophos fertilizer is an organic fertilizer developed by lecturers of Faculty of Agriculture, University of Lampung. The research was aimed to study effect the combination of organonitrophos, and inorganic fertilizers, biochar and the interaction between fertilizer combination and biochar on soil respiration and soil microbial biomass.The research was conducted in the Integrated Field Laboratory of Lampung University using 6x2 factorial in a Randomized Block Design with 3 replications. The first factor was six levels combination of organonitrophos and inorganic fertilizers (P0, P1, P2, P3, P4, and P5). The second factor was two levels of biochar dosage (B0 and B1). Data was analyzed by Analysis of Variance and followed by the Least Significant Difference (LSD)Test at 5% level. The observed variables were soil microorganism activity likely soil respiration and soil microbial biomass. The results showed that P3B1treatment (300 kg Urea ha-1, 125 kg SP-36 ha-1, 100 kg KCl ha-1 + 2500 kg organoitrophos ha-1) was the highest soil respiration at of 60 days after planting (DAP). P5 treatment (5000 kg Organonitrophos ha-1) has the highest soil microbial biomasscompared to other treatments at 60 and 90 DAP. B1 treatment (5000 kg biochar ha-1) has higher soil respiration and soil microbial biomasscompared to treatment (0 kg biochar ha-1. There was an interaction between combination of organonitrophos and inorganic fertilizers and biochar on soil respiration at 90 DAP. However, there was no interaction between fertilizer combination and biochar on soil microbial biomass.Keywords: Biochar, Fertilizer Combination, Organonitrophos, Soil Microbial Biomass Carbon and Soil Respiration

No abstract